SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '16bbc4f681ae1620284c14c88733baae51f4f64ca3eded71a72af224295a2f8b' 
  AND token = 'nGQhJxYFfZvf9wICzdZWPyJ740rN7re9ytlFjD+gPhA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00017

JSON explain

{
  "query_block": {
    "select_id": 1,
    "message": "no matching row in const table"
  }
}